Feed device, particularly for can bodies

Abstract

A pair of catches (74) is mounted on a sliding carriage (20) which is movable forwards and back along a guide (18) between a rear and a front dead centre (C,F), the catches being pivotable backwards and forwards between a working position and a position of rest. In order to move the sliding carriage (20) along the guide (18), a crank drive is provided. This has a crank (30), which can be driven in rotation, and a connecting rod (40), which is connected by a crank pivot joint (36) to the crank (30) and by a connecting-rod pivot point (42) to the sliding carriage (20). A control mechanism allows the catches (74) to assume their working position near the rear dead centre (C) of the sliding carriage (20) for its forward movement and to assume their position of rest near the front dead centre (F) of the sliding carriage (20) for its backward movement. The control mechanism comprises a bistable spring arrangement (44,50) which is disposed between the connecting rod (40) and the catches (74) and assumes each of two stable end positions once during each complete revolution of the crank (30).

I claim: 
     
       1. A feed device, particularly for can bodies (10), having a sliding carriage (20) which is movable forwards and back along a guide (18) between a rear and a front dead centre (C,F),   at least one catch (74) which is mounted on the sliding carriage (20) and can be swung forwards and backwards between a working position and a position of rest,   a crank drive with a crank (30) which can be driven in rotation, and a connecting rod (40) which is connected by a crank pivot joint (36) to the crank (30) and by a connecting-rod pivot joint (42) to the sliding carriage (20) in order to move this along the guide (18), and   a control mechanism which allows the catch (74) to assume its working position near the rear dead centre (C) of the sliding carriage (20) for its forward movement and to assume its position of rest near the front dead centre (F) of the sliding carriage (20) for its backward movement, characterized in that the control mechanism comprises a bistable spring arrangement (44, 50) which is disposed between the connecting rod (40) and the catch (74) and assumes each of two stable end positions once during each complete revolution of the crank (30).   
     
     
       2. A feed device according to claim 1, characterized in that the bistable spring arrangement (44, 50) comprises a rocker (44) which is pivotable about the connecting-rod joint (42) and is connected to the connecting rod (40) by a spring (50). 
     
     
       3. A feed device according to claim 2, characterized in that the spring (50) is a tension spring which is eccentrically suspended on the rocker (44). 
     
     
       4. A feed device according to claim 2, characterized in that the rocker (44) carries a cam follower member (90) which, in the region of the rear dead centre (C) of the sliding carriage (20), runs onto a blocking cam (84) which prevents the bistable spring arrangement (44, 50) from snapping over prematurely into its position corresponding to the working position of the catch (74). 
     
     
       5. A feed device according to claim 2, characterized in that the rocker (44) is connected by a quadrilateral linkage (52, 54, 56, 58) to a catch control shaft (60) mounted on the sliding carriage (20). 
     
     
       6. A feed device according to claim 5, characterized in that the quadrilateral linkage (52, 54, 56, 58) comprises a coupling bar (54) of adjustable length. 
     
     
       7. A feed device according to claim 1, characterized in that the connecting rod (40) carries a cam (64) which forces the catch or catches (74) into their working position near the rear dead centre (C) of the sliding carriage (20) and then prevents them from rebounding. 
     
     
       8. A feed device according to claim 5, characterized in that the quadrilateral linkage (52, 54, 56, 58) comprises a rocking lever (58) which carries a cam follower member (62) corresponding with the cam (64).